Ultrasonic transducer and clamp-on ultrasonic flowmeter

Abstract

The invention relates to an ultrasonic transducer (10) of a clamp-on ultrasonic flowmeter (1) for measuring a measurement variable of a medium in a measuring tube (50), comprising: a transducer element (12) for generating and detecting ultrasonic signals; a housing (11) with a housing chamber (11.1) in which the transducer element is arranged, wherein the housing has at least two second contact points (11.2) which are designed to come in contact with the measuring tube; an extension arm (13) having at least two first contact points (13.2) which are designed to come in contact with the measuring tube, wherein the extension arm has a central region (13.12), a first end (13.11) and a second end (13.13) opposite the first end, the first end being connected to the housing, and the second end being designed to be mounted on the measuring tube, characterised in that a magnetic device (14), by means of which the ultrasonic transducer can be secured to a magnetic measuring tube, is arranged in the central region of the extension arm.

Description

[0001] Ultrasonic transducer and clamp-on ultrasonic measuring device

[0002] The invention relates to an ultrasonic transducer and a clamp-on ultrasonic measuring device.

[0003] The secure and robust attachment of clamp-on ultrasonic transducers to measuring tubes is a problem that has not yet been fully solved.

[0004] For example, this is achieved using tensioning straps, as shown in DE102004052489A1, which, however, quickly becomes unwieldy, at least with larger measuring tube diameters.

[0005] Alternatively, several magnets are used, which are arranged in spatial proximity to the ultrasonic transducer circumferentially around the ultrasonic transducer, see for example US8151651 B1, or parallel to a measuring tube axis, see US4735097.

[0006] However, the material costs of magnets are not cheap.

[0007] The object of the invention is therefore to propose a simple and robust fastening of a clamp-on ultrasonic transducer by means of a single magnet.

[0008] The object is achieved by an ultrasonic transducer according to independent claim 1 and by a clamp-on ultrasonic flowmeter according to independent claim 9.

[0009] An ultrasonic transducer according to the invention of a clamp-on ultrasonic measuring device for measuring a measured variable of a medium located in a measuring tube, comprises: a transducer element for generating and detecting ultrasonic signals; a housing with a housing chamber, in which housing chamber the transducer element is arranged; a boom which has at least two first support points which are designed to be contacted with the measuring tube, wherein the boom has a central region, a first end and a second end opposite the first end, wherein the first end is connected to the housing, wherein a magnetic device is arranged in the central region of the boom, by means of which magnetic device the ultrasonic transducer can be fixed to a magnetic measuring tube, wherein the magnet is arranged between the first support points and the housing.

[0010] In this way, the ultrasonic transducer can be stably and securely mounted on a magnetic measuring tube. In one embodiment, the magnetic device comprises a magnet and a fastening device, by means of which the magnet is fixed to the boom.

[0011] For example, such a magnet can be made of neodymium. For example, such a magnet can be designed as a pot magnet.

[0012] In one embodiment, the fastening device has a fastening rod which is inserted into a bore of the magnet at a first end of the fastening rod and is firmly connected to the magnet in the axial direction, wherein the fastening rod extends through an opening of the boom, wherein a receptacle of the fastening rod, such as a nut, is fastened to a second end of the fastening rod, which is designed to transmit a force imparted by the magnet to the boom.

[0013] The connection between the magnet and the fastening rod or the holder of the fastening rod and the fastening rod can be made, for example, via a thread, or via a groove-engagement connection, via a snap mechanism or similar.

[0014] In one embodiment, the first support points and the second support points are each arranged mirror-symmetrically to one another with respect to a longitudinal section plane of the housing.

[0015] In this way, the ultrasonic transducer can be mounted particularly stably and securely on a magnetic measuring tube.

[0016] In one embodiment, the housing has at least two second support points which are designed to be contacted with the measuring tube;

[0017] A clamp-on ultrasonic measuring device according to the invention comprises: at least two ultrasonic transducers according to one of the preceding claims, which are arranged on a magnetic measuring tube; an electronic measuring / operating circuit for operating the ultrasonic transducers and for detecting measurement signals from the ultrasonic transducers and providing measured values ​​of a measured variable, wherein at least two ultrasonic transducers of different ultrasonic transducers are configured to transmit and receive ultrasonic signals among each other, for example according to the transit time or transit time difference principle.

[0018] Magnetic measuring tubes can, for example, be made of carbon steel.

[0019] In one embodiment, a contact point of the magnet on the measuring tube and a contact point of the transducer element on the measuring tube lie in a plane through a longitudinal axis of the measuring tube. In one embodiment, the measuring tube has an outer diameter of at least 200 millimeters.

[0020] In the following, the invention is described using exemplary embodiments.

[0021] Figs. 1 a) to 1 d) show various views and a section of an exemplary ultrasonic transducer according to the invention.

[0022] Fig. 2 a) outlines a section through an exemplary clamp-on ultrasonic measuring device according to the invention and Fig. 2 b) outlines a section through an exemplary ultrasonic transducer according to the invention with transducer element.

[0023] Fig. 1 a) shows an oblique view of an exemplary ultrasonic transducer 10 according to the invention, arranged on a magnetic measuring tube 50. The ultrasonic transducer has a housing 11 for a transducer element 12, which is arranged in a housing chamber 11.1 of the housing, see also Fig. 1 b). As shown here, the housing can have second support points 11.2, by means of which it rests on the measuring tube. A boom 13 connected to the housing has first support points 13.2, by means of which the boom rests on the measuring tube. As shown here, the housing and boom can be formed as a single piece. Alternatively, the boom can also be detachably fastened to the housing. The boom has a first end 13.11 connected to the housing, a central region 13.12 and a second end 13.13, wherein the second support points are located in the region of the second end.According to the invention, a magnetic device 14 is provided in the central region to attach the ultrasonic transducer to the magnetic measuring tube.

[0024] As shown in Fig. 1 b), the magnetic device has a magnet 14.1 in contact with the measuring tube 50, wherein a contact line of the magnet on the measuring tube and a contact line of the transducer element on the measuring tube preferably lie in a plane through a longitudinal axis of the measuring tube. For example, such a magnet can comprise neodymium. For example, such a magnet can be designed as a pot magnet as shown here. A fastening device 14.2 fixes the magnet to the boom, wherein the fastening device 14.2 has a fastening rod 14.21, which is inserted at a first end 14.211 of the fastening rod into a bore in the magnet and is firmly connected to the magnet in the axial direction, wherein the fastening rod extends through an opening in the boom, wherein a receptacle for the fastening rod 14 is provided at a second end 14.212 of the fastening rod.3, such as a nut, which is designed to transmit a force imparted by the magnet to the boom. The connection between the magnet and the mounting rod, or the receptacle of the mounting rod and the mounting rod, can be made, for example, via a thread, a groove-engagement connection, a snap mechanism, or the like. Fig. 1 c) shows a front view of the ultrasonic transducer with the first support points 11.2, and Fig. 1 d) shows a rear view with the second support points 13.2.

[0025] In one embodiment, the first support points 11.2 and the second support points 13.2 are arranged mirror-symmetrically to one another with respect to a longitudinal section plane of the housing and in particular with respect to a plane through a measuring tube longitudinal axis.

[0026] Fig. 2 a) outlines a longitudinal section through an exemplary clamp-on ultrasonic measuring device 1 with two ultrasonic transducers 10 according to the invention, which are arranged on an outer side of the measuring tube 50, and with an electronic measuring / operating circuit for operating the ultrasonic transducers, for detecting and evaluating measuring signals of the ultrasonic transducers and for providing measured values.

[0027] Ultrasonic transducers of a clamp-on ultrasonic measuring device can send and receive ultrasonic signals from each other, for example according to the time-of-flight or time-of-flight difference principle.

[0028] Fig. 2 b) sketches an enlargement of the longitudinal section of Fig. 2 a) through an ultrasonic transducer 10, wherein a transducer element 12 is held by a holder in the housing chamber 11.1 of the housing.

[0029] List of reference symbols

[0030] 1 clamp-on ultrasonic measuring device

[0031] 10 ultrasonic transducers

[0032] 11 housings

[0033] 11.1 Housing chamber

[0034] 11.2 second support points

[0035] 12 converter element

[0036] 12.1 Mounting bracket for transducer element

[0037] 13 booms

[0038] 13.11 first end of the boom

[0039] 13.12 Middle section of the boom

[0040] 13.13 second end of the boom

[0041] 13.2 first support points

[0042] 14 Magnetic device

[0043] 14.1 Magnet

[0044] 14.2 Fastening device

[0045] 14.21 Mounting rod

[0046] 14,211 first end

[0047] 14,212 second end

[0048] 14.3 Mounting the mounting rod

[0049] 20 electronic measuring / operating circuit

[0050] 50 measuring tube

Claims

Patent claims 1. Ultrasonic transducer (10) of a clamp-on ultrasonic measuring device (1) for measuring a quantity of a medium located in a measuring tube (50), comprising: a transducer element (12) for generating and detecting ultrasonic signals; a housing (11) with a housing chamber (11.1) in which the transducer element is arranged, a boom (13) which has at least two first support points (13.2) which are configured to be contacted with the measuring tube (50), wherein the boom (13) has a central region (13.12), a first end (13.11) and a second end (13.13) opposite the first end, wherein the first end (13.11) is connected to the housing (11), characterized in that a magnetic device (14) with one, in particular exactly one, magnet (14.1) is arranged in the central region of the boom (13), by means of which the ultrasonic transducer (10) can be fixed to a magnetic measuring tube (50), wherein the magnet (14.1) is located between the first support points and the housing (11).

2. Ultrasonic transducer according to claim 1, wherein the magnet device (14) has a fastening device (14.2) by means of which fastening device (14.2) the magnet (14.1) is fixed to the boom (13).

3. Ultrasonic transducer according to claim 2, wherein the fastening device (14.2) has a fastening rod (14.21) which is inserted at a first end (14.211) of the fastening rod into a bore of the magnet (14.1) and is rigidly connected to the magnet (14.1) in an axial direction, wherein the fastening rod (14.2) passes through an opening of the boom (13).

4. Ultrasonic transducer according to claim 3, wherein a receptacle (14.3) of the mounting rod (14.2), such as a nut, is attached to a second end (14.212) of the mounting rod, which is configured to transmit a force mediated by the magnet (14.1) to the boom (13).

5. Ultrasound transducer according to one of the preceding claims, wherein the first support points (11 .2) and the second support points (13.2) are arranged in a mirror-symmetrical manner with respect to a longitudinal section plane of the housing (11).

6. Ultrasonic transducer according to one of the preceding claims, wherein magnet (14.1) and transducer element (12) each have, in particular exactly, a contact line for contacting the measuring tube (50), wherein the, in particular exactly one, contact lines are arranged to be arranged in a plane through a longitudinal axis of the measuring tube.

7. Ultrasound transducer according to one of the preceding claims, wherein the magnet (14.1) has a planar magnetic surface in which the bearing line runs.

8. Ultrasonic transducer according to one of the preceding claims, wherein the housing has at least two, in particular spaced apart from each other, second support points (11 .2) which are designed to be contacted with the measuring tube.

9. Clamp-on ultrasonic measuring device (1) comprising: at least two ultrasonic transducers (10) according to one of the preceding claims, which are arranged on a magnetic measuring tube; an electronic measuring / operating circuit (20) for operating the ultrasonic transducers and for acquiring measurement signals from the ultrasonic transducers and providing measured values ​​of a measured quantity, wherein at least two ultrasonic transducers of the at least two ultrasonic transducers are configured to transmit and receive ultrasonic signals to each other, for example according to the time-of-flight or time-of-flight difference principle.

10. Clamp-on ultrasonic measuring device according to claim 9, wherein magnet (14.1) and transducer element (12) each have a, in particular exactly one, contact line for contacting the measuring tube, wherein the contact points lie in a plane through a longitudinal axis of the measuring tube.

11. Clamp-on ultrasonic measuring device according to one of claims 9 or 10, wherein the magnet (14.1) has a planar magnetic surface in which the support line runs, wherein the magnet (14.1) is oriented such that when the clamp-on ultrasonic measuring device (1) is attached to the measuring tube (50) the planar magnetic surface is directed towards an outer surface of the measuring tube (50) and only the contact line is in contact with the outer surface of the measuring tube and the rest of the planar magnetic surface is spaced away from the outer surface.

12. Clamp-on ultrasonic measuring device according to claims 9 to 11, wherein the measuring tube (50) has an outer diameter of at least 200 millimeters.

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